Though I strongly believed there's no way someone could hack into my hosting account, it occurred to me (actually, some guy sent me an e-mail) that there might be a vulnerability in WP 2.8.4.
Though I checked out each and every single file of my template and plugins, I've found no problem. I usually set cue permissions so no one could actually break into my template and deface it.
Anyway, if I couldn't find anything regarding the tons of links that could be viewed from in "page source", I checked out the SQL database. I thought it might have been some SQL injection. None whatsoever.
I had to reinstall WP. And because I was in a hurry (and I'm not a coder), I didn't got to look in the WP core files.
Still, knowing that I had a new HTML file code inserted into my page source, starting with the HTML tag, continued by the BODY tag, and noticing that was posted right after the footer ending, I believe the problem is somewhere in the files that create the wp_footer function/action.
I had a similar link injection problem before, and generally speaking, the link injection usually appears before your HTML code, not after. It's usually inserted in the HEAD area or below.
Have any ideas? Could anyone check it out?